The Flow Cytometry and Cell Sorting Facility was created by the ACC in 1980, and has been continuously approved and funded by the NCI Core Support Grant since 1981. In the last competitive renewal, this shared resource received an outstanding merit evaluation. Jonni Moore, Ph.D., Professor of Pathology and Laboratory Medicine, has directed the Facility since 1990. She has a doctorate in immunology with over 25 years of flow cytometry experience and frequently serves as an expert consultant to industry and academia. Charies Pletcher, MCI, Technical Director, has been with the Facility since 1987. The laboratory has remained committed to its mission of providing all investigators at the University of Pennsylvania with access to high quality, cost effective services, as well as the scientific expertise necessary to use this technology in their research efforts. This facility is currently recognized as one of the largest and most comprehensive academic flow cytometry shared resources in the United States, offering access to a broad range of analytical and sorting cytometers, expert consultation and an extensive educational program. During the current project period, the Flow Cytometry and Cell Sorting Facility has remained the most frequently used shared resource of the Abramson Cancer Center and has continued to experience growth. Overall usage has increased by 63% (based on usage hours) during the current project period. Over 100 ACC members have used the facility in the past year, with 54% of total usage by ACC members. CCSG support represents 16% of the proposed facility budget with the remaining funding coming from charge backs and institutional support. The success of the core has been facilitated by the addition of instrumentation, recruitment of staff, expansion of training programs and the increased interest in cytomics within the ACC membership.